When Brad Pitt and Angelina Jolie want privacy with their brood of six, they retreat to their 880-acre Chateau Miraval estate in the South of France. But are they shelling out some serious bucks to turn the estimated $60 million property into a showplace worthy of their fame and fortune?

The London Sunday Mirror claims the A-list parents are spending more than $16 million to update the 17th-century spread, for which they reportedly signed a three-year lease-to-own deal in 2008. (Other estimates have put the price tag for the renovations at a more reasonable -- at least by Hollywood standards -- $5 million.)

"They want to make sure this very romantic property becomes the love nest of all love nests," a local property developer tells the paper.

Among the updates that architecture buff Brad and the seemingly patient-with-Brad's-building-hobby Angelina are said to be planning are a "contemporary" redo of all 35 rooms of the chateau (or 35 bedrooms, depending on which source you believe -- we're still awaiting our invitation so we can count for ourselves), along with an upgraded wine cellar, new Jacuzzis, steam rooms, a spa, and gym.

Celebrity amenities will purportedly include an overhauled helicopter landing pad; a motorcycle track for Pitt; and a state-of-the-art, infrared sensor-inclusive security system that will seemingly be able to locate Maddox, 8, Pax, 5, Zahara, 4, Shiloh, 3, and 1-year-old twins Vivienne and Knox should they ever become lost among the home's moats, olive groves, forest, and 20-odd fountains.

Word is, the remodel has already begun, with the actor reportedly making a brief stop at the chateau to check on the progress in late July following the Berlin premiere of "Inglourious Basterds."

"The application has been received for widespread work on their new house," says Jean-Claude Sadion, mayor of the town of Correns, which is within baguette-tossing distance of the Jolie-Pitt's rarefied residence, "and we are delighted that they will be here more permanently."

The nomadic clan is apparently planning to hole up at the palatial pad for the rest of the summer, and they have already made themselves at home. Last Thursday, Brad and Angelina helped Maddox and Pax pick out gerbils and goldfish at a local pet store. The day before, the ridiculously famous flames treated Shiloh and Zahara to lunch at a café.

According to Radar, the aesthetically detail-oriented Pitt is also designing furniture for the house, a custom job that will set him back around $500,000, a price that doesn't include the cost of the stain removal and repairs that will surely be needed once six rambunctious kids get their sticky hands on the one-of-a-kind pieces.

"We're trying to spend more time in the South of France," Brad told Parade magazine earlier this month, "because our kids have a more normal life there."

In related real estate news, Pitt's former fiancée Gwyneth Paltrow is apparently bucking the current economic trend by upsizing. Britain's Daily Mail says the GOOP-y Oscar winner and her husband, Chris Martin, have started renovations on their luxurious London townhome with the intention of forming an $11 million-plus "superhouse."

Seems they purchased the adjoining property and are preparing to blast out the connecting walls to give them twice the amount of living space (Gwyn's pal Madonna did something similar with her London abode, buying the place next door and converting it into -- shocker -- a gym). They are also building a two-story addition that will feature three bedrooms and a gym.

Once the merger is complete, the couple's new digs will reportedly have a whopping 33 rooms, plenty of space for kids Apple, 5, and Moses, 3, to run around.

"It will be a massive house," notes a neighbor. "What they have already is a substantial family home, but to double and add a bit on will make it a real mansion."